Image sensors capable of capturing depth information have been proposed. For example, time of flight (ToF) sensors operate by transmitting a light signal into an image scene, and then detecting the return light signal reflected by objects in the image scene. By calculating the time of flight of the light signal, the distance from the sensor of objects in the image scene can be estimated. For example, the pixels of such a sensor could be based on SPADs (single photon avalanche diodes).
For some applications, it would be desirable to be able to capture both a 2D image of a scene, and a corresponding depth image of the scene.
While one solution for achieving this could be to use separate image sensors to capture the 2D image and the depth image, such a solution is non-optimal in view of the fact that these image sensors will have different viewpoints of the image scene, leading to a misalignment between the pixels of the corresponding images. Furthermore, the use of two sensors would add volume and cost to the device.
Another solution would be to integrate both 2D image pixels and depth pixels within a same sensor array. However, a problem is that the depth pixels generally have significantly larger dimensions that 2D image pixels, making such an integration complex.